Identification Tips

Below are details of how to identify the most commonly reported species off the West of Scotland. If you have any doubt as to the identification of the animal, then the most important features to record are: colouration; size; shape; behaviour and if possible, also its surfacing motion.

Porpoise
About 1.5m in length; the smallest cetacean that will be seen
Small equilateral dorsal fin - only part of animal that's seen when it surfaces for air
Very seldom leaves the water
Surfaces with a slow, rolling motion - a particularly distinctive characteristic
Blow is rarely seen, but makes a sound rather like a sneeze - a puffing noise, rather than a sharp inhalation
Seen in coastal waters, rarely in depths of over 110m
Ususally wary of boats, but if associating then they will swim in the wake rather than bow-ride
Can be seen in pretty much any group size, but most often less than 10
Dark grey/black colour with lighter ventral surface
Will surface to breathe 4 times every 10-20 seconds before diving for about 6 minutes

Minke whale
Between 7 and 7.5 m long (males normally under 7, females larger)
Seen either singly, in pairs or threes, only occasionally more. Really only see mother and calf as a pair
Body is slender and streamlined, head is pointed and triangular no beak
Is a single ridge beginning at tip of snout and ending in front of the blowholes
Sharply pointed snout breaks the surface first
Strongly curved/sickle shaped dorsal fin located 2/3 of the way down the length of the body and looks disproportionately small compared to body size
Kittiwakes, young gulls and manx shearwaters associate when feeding
Baleen is sometimes visible when feeding - mostly yellowish white with fine bristles Black/dark grey colour and white on belly and underside of flippers
Have a diagonal band of white on the upper surface of each flipper
Low, bushy and inconspicuous blow (2-3m) often not seen
In general has unscarred skin - may help distinguish it from other species
Very inquisitive species and often approach boats (especially stationary vessels) Irregular breathing rate
Does 3 (sometimes 2) shallow dives then a deep dive
Usually surface once or twice before diving

Bottlenose Dolphin
Are up to 4m in length
Large and well-built, robust dolphins
Have blunt, stubby beaks Grey coloured with a slightly darker back and paler underside
Usually seen in groups of 6-12
Swim close to the shoreline
Are active and playful, may leap out of the water and 'tail-slap' or bow-ride boats
Are the most widespread of all dolphin

Killer whale
Average is 6-7m in length, but the males can get up to 10m
Group size ranges from 1-100 but average is 5-20
Dorsal fin is very conspicuous and is situated in the middle of the back. Male fin at right-angles to body, can be 1.8m tall; female and young have a slightly smaller and more curved fin - although still much taller than most similar sized cetaceans
Stark black and white colouration - black dominant on back, white dominant on belly
In general, prefer deep water but may be found in shallow bays and estuaries
Can be confused with false killer whales but they are all black with grey patches and a more slender body.
Can travel up to 55 km an hour
Flippers large, broad, rounded and paddle-shaped and especially obvious when breaching or spy-hopping

Common dolphin
About 2m long
Fine stream-lined body and long tapering beak/mouth
Dorsal fin is curved and pointed
Has a distinctive yellow-cream dorsal - grey ventral colour contrast with hourglass shape on its side
Very active and acrobatic, frequently bow-ride, breach and slap water with chin and tail Are a pelagic species (mostly seen along or seaward of 100 fathom contour)
Seen in pairs or groups of less than 10, but can be in the hundreds or thousands
Often associated with gannets
Their movements may be related to prey migrations eg. mackerel in winter and spawning herring in summer
Sharp angle between beak and forehead

Risso's dolphin
Average of 3.5m long
Large, stocky body
Much larger forehead (melon) than other species and no beak
Silver-grey/ cream white colour because of the large number of scars and scratches on the body. Therefore, younger individuals are darker
Dorsal and pectoral fins darker than the rest of the body
Usually seen in water 1000m deep
Curved dorsal fin, ½ way down body
When surfacing, head and dorsal fin are seen. Before diving often raise tail out of water and dive vertically
Rarely seen singly or in pairs. Instead, their average group size is usually 10+ Active like the common dolphin - breach and tail/chin slap the water

White-sided dolphin
About 2.5m long
Back is black/dark grey with white band along sides and yellow band on each side of tail stock, usually visible when the dolphin surfaces to breathe
Tall, strongly falcate (curved) dorsal fin in the middle of the back
Seen offshore, often along 50 fathom isobar
Will leap clear of water when traveling
In this part of the world, the white-beaked has an all-white beak
Eat squid, mackerel, herring, shrimp and smelt
Much larger pods are seen further offshore - up to 1000. But 6-30 nearer land
Seen mainly between June and November, may move further north after that may be confused with the white-beaked dolphin, but the white-sided is slightly smaller and slimmer. Tan blaze on each side of tail stock is also a giveaway. White beaked also has a white aspect behind the dorsal fin which the white-sided is entirely without. Common dolphin has a longer and more slender beak, slimmer body and hourglass pattern and are not as shy as white-sided are
Only found in the north Atlantic
Calving season is between April and July off the U.K.

White-beaked dolphin
Up to 3m long, but average adult length is 2.6m
Are heavily built with blunt and rounded pale grey/white heads and beaks
Are black with chalk white patches along sides, over tail, head and beak
Are fast powerful swimmers
Feed in coastal areas right up to the shore and even in harbour mouths, although they tend to congregate around the shelf edge
Are generalist feeders- eat flatfish, shrimp and squid, as well as herring and mackerel etc.
Found in groups from a few individuals up to 100s, but the most common groups size is <10
Calves are thought to be born between June and September
Are more likely to be seen off the north-west of Scotland than the south-west
May be confused with white-sided dolphins, but the white-beaked is larger, more robust and does not have the yellowish blazes on its sides. There is a graduation of colour on the white-beaked, as opposed to more definite colour changes and markings on the white-sided. The white-sided dolphin also does not have any white on its back behind the dorsal fin and finally, it also tends to prefer more pelagic areas

Basking shark
Second largest fish of the world
Length: 3 –9m
Very large, rather stout shark; dark slate-grey, olive-grey or nearly black dorsal side, slightly lighter ventral side; gill slits almost encircling the head; pointed snout and vast cavernous mouth with tiny hooked teeth.
Mostly spotted singly or in small groups, cruising slowly at the surface filter-feeding with the mouth agape and dorsal fin exposed.

For more information on basking sharks why not visit The Marine Conservation Society website and read about their Basking Shark Sighting Project.

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